Mexican Americans are the largest minorities in South Texas, and have a strong predilection for non-insulin dependent diabetes mellitus (NIDDM); the rate of NIDDM among Mexican Americans is more than twice that of the general population. Certain oral health parameters such as root caries is not well documented among this group of minorities. With an increasing elderly population and decline in childhood dental (coronal) caries, more and more teeth are being retained in the oral cavity. Retained teeth/toothsurfaces (both coronal and root) may be at a risk to dental caries. Apart from the apparent beneficial role of fluoride on root caries, analytical epidemiologic studies on root caries have been described as "rudimentary, inadequate, and even non-existent." A case-control study is being proposed to investigate any association between non-insulin dependent diabetes mellitus and root surface caries, as well as between root caries and other risk factors. The study population will consist of 100 volunteer subjects, aged 25-64 years, drawn from the ongoing longitudinal San Antonio Heart Study (SAHS) which has been studying the risk factors for diabetes and cardiovascular diseases among Mexican Americans for nearly 15 years. Fifty cases (diabetes), and 50 age- and gender-matched controls (those without diabetes) will be selected. Dental examinations will be conducted on both cases and controls, and will include coronal caries, root caries, periodontal status, gingival recession, oral hygiene status, and soft tissue lesions. These examinations will be conducted in the Clinical Research Facility at the Dental School. Clinical data will be entered directly into laptop computers using the appropriate software. Direct data entry will minimize certain potential sources of errors. Whole parotid saliva will be collected for assessing salivary flow rate and certain microbial organisms (Mutans Streptococci and Lactobacilli). Data on residence, medications, demographics, relevant medical histories, diabetes status, degree of control of diabetes, diet history, and acculturation will be abstracted from the comprehensive data bank of SAHS. Statistical analysis will include both descriptive and analytical tests. Descriptive statistics will assess the prevalence and severity of all dental conditions under investigation. Analytical tests both bi- and multivariate (general linear regression and logistic regression models), will investigate the association between root caries and diabetes, as well as other relevant variables. Relation between diabetes and other dental conditions (coronal caries, periodontal diseases, etc.) will also be investigated. Given the positive association between diabetes and periodontal diseases, as well as the latter and root caries, results may indicate a positive association between diabetes and root caries. Findings from this study could be further confirmed by a large- scale, population-based epidemiological studies, and will play a vital role in enhancing the early detection and prevention of both NIDDM and root caries.